1. Field of the Invention
The present invention relates to a semiconductor device manufacturing apparatus, and more particularly to such apparatus for processing a wafer with processing liquid such as developer.
2. Description of the Prior Art
The conventional wafer processing apparatus are generally classified into:
(1) a spray system in which processing liquid is sprayed from above onto a wafer supported on a spinner chuck;
(2) a dip system in which a carrier containing 1 to 25 wafers is dipped in a dip bath containing the processing liquid; and
(3) a paddle system in which a small amount of processing liquid is dropped onto a wafer supported on a spinner chuck to process said wafer, and is then removed by the centrifugal force by rotation of the spinner chuck.
However the spray system (1) is associated with the drawbacks of being susceptible to dust contamination because the wafer is placed upwards; instability in processing because of difficult precise temperature control of the processing liquid; unevenness in processing due to uneven liquid spraying; unsuitability for electron beam photoresists since the composition of processing liquid composed of mixed solvents used for such electron beam photoresists may vary in spraying due to the difference in the vapor pressure of one of said mixed solvents; unevenness in processing, which proceeds faster in the peripheral area of the wafer; and pinhole formation in the photoresist caused by the remaining mist of the sprayed processing liquid which is concentrated in the drying step after processing and drops onto the photoresist.
On the other hand, the dip system (2) is associated with the drawbacks of requiring a large amount of the processing liquid; unstable and uneven processing of the process among the wafers of a lot and between different wafer lots; cumbersome drying of the processed wafers which cannot be easily automated; and difficulty of processing with mixed solvents.
Also the paddle system (3) is associated with the drawbacks of being susceptible to dust contamination because the wafer is placed upwards; difficulty in precise temperature control of the processing liquid; unevenness in processing, which proceeds faster in the peripheral area of the wafer; and unsuitability for processing with mixed solvents.